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Improved method for depositing CeO2 by ALD (atomic layer deposition) method

A certain amount of catalyst technology, applied in separation methods, chemical instruments and methods, chemical/physical processes, etc., can solve the problems of sintering deactivation of precious metal components, reduce purification efficiency, and high price, and achieve excellent high temperature thermal stability. Effect

Pending Publication Date: 2021-07-02
BEIJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the most effective catalyst for purifying automobile exhaust gas, that is, noble metal (Pt, Rh, Pd) supported catalyst is the active component of the three-way catalyst for automobiles. After sintering deactivation, its catalytic activity is greatly reduced, which greatly reduces the purification efficiency. Given that precious metals are expensive and difficult to replace with other components, how to improve the thermal stability of catalysts is one of the biggest problems currently facing
[0003] At present, three-way catalysts are mainly supported three-way catalysts. The active sites of the catalyst are located at the metal-oxide interface, and the particle size of the noble metal particles affects the activity of the catalyst. The smaller the noble metal particles, the larger the specific surface area, showing more Excellent catalytic activity, but the sintering of noble metal particles will lead to a decrease in catalyst activity, so it is of great significance to protect noble metal particles

Method used

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  • Improved method for depositing CeO2 by ALD (atomic layer deposition) method
  • Improved method for depositing CeO2 by ALD (atomic layer deposition) method
  • Improved method for depositing CeO2 by ALD (atomic layer deposition) method

Examples

Experimental program
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Effect test

Embodiment 1

[0036] Take a certain amount of commercial catalyst PD / Al 2 O 3 Remember to 1 # catalyst sample, 1 # catalyst is placed in a muffle furnace, ranging from the room temperature from the air atmosphere to 800 ° C from the air atmosphere, and the aging catalyst is obtained. Sample of 2 # catalyst sample.

Embodiment 2

[0038] 1 # catalyst sample 1g in Example 1 was placed in a polytetrafluoroethylene liner, then placed in a glove box of an argon atmosphere, 5.6 mg Ce (TMHD) was taken out. 4 In the polytetrafluoroethylene liner, it is mixed with a 1 # catalyst, and the cover is sealed, then placed in an oven, the temperature rise rate of 5 ° C / min is raised from the room to 180 ° C, heat insulation 15 min; then from the oven; then from the oven; Take it out, open the cover to expose in the air, put it into the muffle, raised from the room temperature to 400 ° C from the room at 5 ° C / min; repeat the above step 10 times, resulting in ALD 10CYCLE PD / Al 2 O 3 @Ceo 2 , Records 3 # catalyst samples.

Embodiment 3

[0040] Take the 1 # catalyst sample 1g in Example 1, in the polytetrafluoroethylene liner, then put it in a glove box of an argon atmosphere, remove 11.2 mg Ce (TMHD) 4 In the polytetrafluoroethylene liner, the remaining operation method is in Example 2 to obtain a 4 # catalyst sample.

[0041] Example: 4: 4:

[0042] The 3 # catalyst sample in Example 2 was placed in a muffle. Under the air atmosphere, the temperature rise rate of 5 ° C / min was raised from the room to 800 ° C, heat preservation of 5 h, resulting in an aging catalyst, recorded as 5 # Catalyst sample.

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Abstract

An improved method for depositing CeO2 by an ALD (atomic layer deposition) method relates to the technical field of noble metal catalysis, and mainly comprises the following steps: weighing a certain amount of tetra (tetramethyl heptadione) cerium and a certain amount of commercial catalyst Pd / Al2O3 in a glove box, mixing, putting into a polytetrafluoroethylene lining, sealing, taking out, putting into a drying oven, heating, taking out and putting into a muffle furnace, roasting in an air atmosphere to obtain a Pd / Al2O3 coated CeO2 catalyst, and repeating the steps to obtain CeO2 layers with different deposition thicknesses. CeO2 is used as a protective layer, so that the thermal stability of the catalyst is improved, and the catalyst still keeps relatively high catalytic activity after being aged at 800 DEG C.

Description

Technical field [0001] PD / Al by this invention using improved atomic layer deposition (ALD) technology 2 O 3 Catalysts are modified, deposited in the surface of the catalyst to deposit a layer of CEO 2 , Improve the thermal stability of the catalyst involve the preparation method of ALD deposition, belonging to the technical field of metal load type catalyst. Background technique [0002] In recent years, my country's economic rapid development, the people's living standards have been greatly improved, and my country's auto industry has also developed rapidly, and the number of motor vehicles has increased, and the per capita vehicle guarantee has been improved, but while the living standard is improved, the car exhaust gas leads to the deterioration of the environment It is also more serious, and with the improvement of the people's environmental awareness, the state and the government have also formulated the relevant provisions of exhaust emissions. From July 1, 2020, all sa...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J23/63B01D53/94B01D53/62B01D53/72B01D53/56
CPCB01J23/63B01D53/945B01D2258/01Y02T10/12
Inventor 张桂臻徐亚蒙何洪何泽源李淑贞
Owner BEIJING UNIV OF TECH